Table 8.11 : Electronic configuration and atomic ionic radii of lanthanoids
Element
Symbol
Atomic number
Electronic configuration
Atomic radii, pm
Ionic radii
(Ln
+3,
6-coordinate),
pm
Expected
(ground state)
Observed(ground
state)
(+2 oxidation state)
(+3 oxidation state)
Lanthanum
La
57
[Xe]4f
0 5d
1 6s
2
[Xe]4f
0 5d
1 6s
2
4f
0 , 5d
1
4f
0
187
103
Cerium
Ce
58
[Xe]4f
2 6s
2
[Xe]4f
1 5d
1 6s
2
4f
2
4f
1
183
102
Praseodymium
Pr
59
[Xe]4f
3 6s
2
[Xe]4f
3 6s
2
4f
3
4f
2
182
99
Neodymium
Nd
60
[Xe]4f
4 6s
2
[Xe]4f
4 6s
2
4f
4
............
181
98.3
Promethium
Pm
61
[Xe]4f
5 6s
2
[Xe]4f
5 6s
2
4f
5
............
181
97
Samarium
Sm
61
[Xe]4f
6 6s
2
[Xe]4f
6 6s
2
4f
6
4f
5
180
95.8
Europium
Eu
63
[Xe]4f
7 6s
2
[Xe]4f
7 6s
2
4f
7
4f
6
199
94.7
Gadolinium
Gd
64
[Xe]4f
8 6s
2
[Xe]4f
7 5d
1 6s
2
4f
7 , 5d
1
............
178
93.8
Terbium
Tb
65
[Xe]4f
9 6s
2
[Xe]4f
9 6s
2
4f
9
4f
8
177
92.3
Dysprosium
Dy
66
[Xe]4f
10 6s
2
[Xe]4f
10 6s
2
4f
10
4f
9
176
91.2
Holmium
Ho
67
[Xe]4f
11 6s
2
[Xe]4f
11 6s
2
4f
11
4f
10
175
90.1
Erbium
Er
68
[Xe]4f
12 6s
2
[Xe]4f
12 6s
2
4f
12
............
174
89
Thulium
Tm
69
[Xe]4f
13 6s
2
[Xe]4f
13 6s
2
4f
13
4f
12
173
88
Ytterbium
Yb
70
[Xe]4f
14 6s
2
[Xe]4f
14 6s
2
4f
14
............
86.8
Lutetium
Lu
71
[Xe]4f
14 5d
1 6s
2
[Xe]4f
14 5d
1 6s
2
4f
14 ,
5d
1
4f
14
86.1